Making Plants That Sip, Not Gulp, Water

Mike Mellano, president of the San Diego County Farm Bureau, says the regional water crisis and weak economy has created "a little bit of a perfect storm" for local farmers. Photo: Sam Hodgson

JONATHAN PARKINSON on Jul 1, 2009

Wednesday, July 1, 2009 | For the family farm, the margin between profit and loss is razor thin in the best of times. These are certainly not the best of times for farmers in San Diego County.

The wildfires of 2003 and 2007, coupled with a crippling drought — now in its third year — have forced some local farmers out of business. And, with agriculture accounting for 80 percent of California’s water use, those still in business are being hit hard. They are enduring record water price increases, and, in some cases, mandatory usage cutbacks as high as 30 percent.

“One (water) district was proposing increases of more than 100 percent,” said Mike Mellano, a cut flower producer in Oceanside and president of the San Diego County Farm Bureau. Mellano said the record price increases and rationing, along with the worsening economic climate, have created “a little bit of a perfect storm” for county farmers.

One way to weather the storm is to make crops that don’t need as much water. This is the focus of pioneering research by University of California, San Diego biologist Julian Schroeder. He is a leader among scientists developing a new generation of crops that could ultimately protect agriculture from the scourge of drought. But as with all of humankind’s attempts to improve on nature, Schroeder’s innovation has high hurdles to overcome in both the scientific and cultural realms.

“The bad news is there is no magic bullet,” said Schroeder.

“The good news is that drought-tolerant mechanisms are multifarious,” he adds, meaning there are multiple approaches scientists can take that will yield an improvement.

Schroeder’s lab at UCSD studies a drought-tolerance mechanism involving stomata, microscopic pores found on the leaves of plants that breathe in carbon dioxide. The structures are crucial to photosynthesis, but plants lose up to 95 percent of the water they take in through the stomata.

To conserve water and stay alive during drought conditions, plants narrow or even close the pores in their leaves by making a hormone called abscisic acid. The hormone signals the sausage-shaped guard cells bordering the stomata on the leaf skin to close them off. This strategy means a tradeoff for the plant: Its growth slows to a crawl, but by conserving its water the plant lives to grow another day.

In recent years Schroeder’s lab has discovered ways to improve this natural process, by identifying genes that regulate how abscisic acid works. Through genetic engineering, Schroeder has found alterations to plants that can make them more sensitive to the hormone. The altered plant is then more likely to close its stomata sooner and stay green through a long drought.

Schroeder’s discoveries have already been turned to several practical applications. One Canadian biotech firm, Performance Plants, has used his innovations to develop drought-tolerant varieties of canola, corn and turf grass. Performance Plants has in turn licensed their technology to companies like Syngenta and Scotts MiracleGro for commercialization.

But for all their advantages, these drought-tolerant crops aren’t a perfect solution. The farmers might still end up using the same amount of water on the drought-resistant crops, and just get better yields. However, in times like these, when water is scarce and prices are high, drought-tolerant plants could give farmers a fighting chance.

“Under drought stress, you have yield losses, you can lose 30, 40, 50% of your yield,” Schroeder said. “And if you could reduce that loss by half, that’s a huge improvement.” And for some plants, like turf grass and other ornamentals, drought tolerance could be even more significant since yield is not important in landscape plants.

Schroeder believes the quest for a drought-defying crop is only just beginning. “My view of this field — I see it as being a little like the microelectronics revolution. The first product you could buy back in the 1970s was a transistor radio with a single transistor in it. … And in this field we’re still at those early stages.”

The potential for improvement, Schroeder said, is tremendous and largely untapped. However, exploiting that potential may take time, especially since a new discovery can take anywhere from seven to 15 years to make it to market.

Another approach is being pursued by St. Louis-based Monsanto, which is considered the king of crop biotech. Monsanto has bred a transgenic corn variety using a gene taken from a soil bacteria, and claims to have shown a 6-to-10 percent yield improvement in tests. Ordinarily the gene helps the bacteria withstand cold; in the plant it helps sustain normal growth during a drought. “We hope to have [drought-tolerant corn] on the market roundabout 2012,” said Riddhi Trivedi-St. Clair, a Monsanto spokeswoman.

Monsanto plans to develop a second-generation version as well; its lead rivals, Syngenta and DuPont, are working on drought-tolerant crops they hope to market beginning early next decade.

The innovations with these field crops won’t have a big impact on San Diego County farmers because only a small percentage of the county’s agricultural production is in field crops. But given that 90 percent of San Diego’s water is imported, any reduction in water use statewide indirectly benefits the county. And the next generation of drought-resistant crops could include avocados and strawberries, which are the mainstays of San Diego’s farming industry.

Once on the market, it’s also possible new drought-tolerant crops could excite controversy, like other genetically engineered products before them. When genetically altered crops were first introduced in the mid-1990s, they sparked heated debate that led some countries to require labeling or even ban the new crops outright. The European Union, for instance, imposed a moratorium on genetically engineered crops until 2004, and some EU and Asian countries still regard genetically engineered crops with suspicion.

In the United States, genetically engineered crops have become increasingly common. Today, 92 percent of soybeans and 80 percent of corn grown in the United States is genetically engineered. These crops require approval from both the U.S. Department of Agriculture and the Food and Drug Administration before going on the market.

Skeptics argue that the technology is overrated or that its ramifications may be poorly understood. For example, biotech critics often express concern over cross-pollination of genetically engineered crops with closely related wild species. The resulting wild plants with new traits could change the ecosystem in unpredictable ways.

Opponents also raise political and cultural issues, most prominently that developing nations could become overly dependent on companies from industrialized nations for their food, and that under no circumstance should science mess with nature’s handiwork.

Proponents of genetically engineered crops counter that because crossbreeding or any method of developing a new variety modifies a plant’s genes, genetically engineered crops in their view are no different from any others.

The ongoing controversy means that farmers face an uncertain market for genetically engineered crops. But if this withering dry spell becomes the rule — as many fear — most scientists and farmers agree that one hard truth will win out.

“Regardless of where you’re at or what you’re doing,” said Mellano, the Farm Bureau president, “water is a precious and scarce commodity. People talk about oil. You can live without oil in a lot of instances, but you can’t live without water.”

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